As a power source of a vehicle such as an electric automobile or a hybrid automobile or electrical equipment, there is a battery system including a battery block composed of a plurality of battery cells (also called just “cells”, hereinafter) and a circuit for monitoring the states (voltage, temperature) of the respective battery cells.
In the battery system, conventionally, as a cable which connects the battery cell and the monitoring circuit in order to monitor the states of the respective battery cells, a wire harness, a flexible flat cable (FFC) or a rigid substrate is used.
In Patent Literature 1 and Patent Literature 2, a battery device using a wire harness is disclosed. In Patent Literature 3, a battery module using a flexible flat cable is disclosed. In Patent Literature 4, a battery system using a rigid substrate is disclosed.
Also, in Patent Literatures 3 and 5, electrically connecting a bus bar attached to an electrode of the battery cell to a wiring member of a flexible flat cable or the like by welding or screwing is disclosed.